Heat exchanger structure



March 23, 1965 R. c. THORNTON ETAL 3,174,301

HEAT EXCHANGER STRUCTURE Filed Oct. 7, 1963 F'IGJ United States Patent O "ice 3,174,301 MAT EXCHANGER STRUCTURE Raymond C. Thornton and Roy W. Abbott, lehersontown, Ky., assignors to General Eiectric Company, a corp= ration of New York Fiied Oct. 7, 1963, Ser. No. 314,246 4 Ciaims. (Cl. 62-291) The present invention relates to heat exchangers and is more particularly concerned with heat exchangers comprising one or more serpentine conduits and improved means for supporting and spacing the conduits.

In the construction of heat transfer surfaces such as the condenser or evaporator components of a refrigeration system comprising one or more conduits of serpentine configuration, it is necessary to support the end turns or return bends of the serpentine by some sort of structural member. In the past, this has been done by means of end plates or end sheets which includes slots for receiving the U-shaped end turns. However, these metal end sheets have a nurnber of disadvantages. Relatively expensive dies and tooling are required for their production and the thermal conductivity thereof causes undesired heat transfer to the mounting brackets or the like employed to support the heat exchangers. In addition, when such heat exchangers are employed in refrigeration systems or the like including a compressor which effects pulsating ow of a uid through the heat exchanger, noise and Wear may occur whenever the end sheets lare not in sufhciently firm contact with the conduit to prevent vibrations thereof.

It is an object of the present invention to provide animproved heat exchanger structure including simple and effective means for firmly supporting and insulating the end turns thereof.

Another object of the invention is to provide a heat exchanger structure including a serpentine conduit comprising a plurality of passes connected by end turns and means for supporting the end turns whereby the heat exchanger structure is effectively insulated from its support or mounting means.

A more specific object of the present invention is to provide a heat exchanger particularly useful as the evaporator component of a refrigeration system including a conduit comprising a plurality of horizontal passes series connected by end turns in which the end turns are encapsulated in and completely supported in Vspaced relationship by a rigid plastic foam material.

A still further object of the invention is to provide a combination or unitary evaporator and drip tray structure particularly useful in refrigeration systems in which the support for a serpentine refigerant conduit and the drip tray are composed of a foamed plastic insulating material.

Further objects and advantages of the present invention will become apparent as the following description proceeds `and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In accordance with one embodiment of the present invention, there is provided a unitary heat exchanger structure comprising a iiuid conduit including a plurality of spaced passes series connected by end turns at the opposite ends of the structure and end blocks of rigid foamed plastic material completely embedding and supporting these end turns and forming insulating means for mounting the heat exchanger structure. In a more specific embodiment of the invention, the heat exchanger structure particularly adapted for use as an evaporator component of a refrigerating system also includes an insulated drip tray integrally formed with the end blocks.

For a better understanding of the present invention reference may be had to the accompanying drawing in which:

FIGURE l is a View, partly in section, somewhat schep 3,174,301 Patented Mar. 23,1965

matically illustrating an air conditioning unit including a heat exchanger structure of the present invention;

FIGURE 2 is a sectional view of one embodiment of the heat exchanger of the present invention; and

FIGURE 3 is a view similar to FIGURE 2 illustrating a second embodiment of the present invention in the form of a combination evaporator and drip tray.

Referring now to FIGURE l of the drawing, there is shown an embodiment of the heat exchanger of the present invention in a room air conditioner unit which is adapted to be positioned Within an opening in an outer wall of an enclosure. The unit comprises a casing 1 divided by a barrier 3 into an inner compartment 4 and an outer compartment 5 within which there is mounted respectively an outdoor heat exchanger 7 and an indoor heat exchanger 8. A compressor 9 is also positioned within the outdoor compartment 5 and the compressor 9, the outdoor heat exchanger 7, flow restricting means 10 and the indoor heat exchanger 8 are connected in closed series flow relationship so that the compressor 9 withdraws low pressure refrigerant from the indoor heat exchanger rwhich functions as an evaporator and discharges compressed or high pressure refrigerant into the outdoor heat yexchanger 7.

As the refrigerant flows from the outdoor heat exchanger 7 to the indoor heat exchanger 8 it is expanded by means of a suitable flow restricting means such as a capillary tube 1h.

When the air conditioner is in operation, outdoor air is drawn into the outdoor compartment 5 through an inlet grille 1i by means of a fan 12. The air then passes through the outdoor heat exchanger 7 and is discharged through the discharge grille 13. Indoor air is drawn from within the room by means of a fan 14 and this air stream is discharged through the indoor heat exchanger 8 back into the room through the discharge grille 15. Condensate collecting on the indoor heat exchanger 8 is collected and discharged to the outdoor compartment 5 through a conduit 16 where it is introduced into the air stream circulating through the outdoor compartment 5 by any suitable means (not shown).

While the heat exchanger structure of the present invention is adapted to be used in various applications as for example either ias an evaporator or the condenser component of a refrigeration system, it will be particularly described with reference to the use thereof as an evaporator component of a refrigeration system or more specifically as the evaporator component S of the air conditioner illustrated in FIGURE l.

The novel features of one embodiment of this `evaporatorstructure are shown more clearly in FIGURE 2 of the drawing. With reference to FIGURE 2 there is shown an evaporator structure comprising a refrigerant conduit generally indicated by the numeral 18 bent in serpentine form to provide a plurality of horizontal passes 19 spaced from one another and connected in series connection by means of a plurality of end turns 20. In accordance with the usual practice the horizontal passes 19 may be provided with tins 21 to provide good heat transfer between the refrigerant conducted through the conduit 18 and the air passing through the `evaporator structure.

Instead of the usual sheets of metal or the like, a foamed plastic material is employed for supporting the end turns 2h and for maintaining the various passes 19 in spaced relationship. More specifically, the end turns 20 at each end of the evaporator structure are encapsulated in blocks 22 of a rigid plastic material such as a foamed polyurethane resin or expanded polystyrene beads, either `process hereafter referred to as foaming. By using suitable forms or molds for enclosing the end turns and foaming the resin in place about the end turns, the solid blocks 22 of the foamed resin completely embed and encapsulate the end turns 20. Also since these foamed resins have the property of adhering to surfaces in which the resin Vcomes in contact during the foaming thereof, the end turns are firmly secured or anchored in the resin material which provides the sole 'structure which in turn forms supports for the individual end turns and hence the entire evaporator conduit 18.

If desired one or more metal inserts such as straps 23 may be brazed or otherwise secured to two adjacent end turns 20to provide a more rigid fastening means for mounting the evaporator structure 8 on suitable mounts such as the wall 24 forming part of the case 1 and a supportingbracket 25 positioned within the compartment 4 by means of suitable metal screws 26 or the like.` Since the straps 23 are completely embedded within the oamed insulation and as the screws V26 engaging the straps form the only high conducting heat paths between the evaporator structure and the mounting means, thermal conduction between the evaporator structure and mounting Ybrackets or the like is low.

' which is also composed of the resin foam material is formed integrally with the end sheets or blocks 22 at the time that the end turns 20 are encapsulated by the foamed resin material. This drip tray component 29 includes a sloping base or wall 30 having its low point at the connection with the drain tube y16 and'side Walls such as the side walls 31 and 32 cooperating with the sloping bottom wall 30 to form a receptacle for receiving the condensate for discharge through the drain tube 16. As the drip tray is formed of the foamed plastic material, sweating of the drip tray. normally occurring with metal drip trays is avoided and a lower cost structure is possible due to the fact that the drip tray is formed at the same time in the same operation as the end sheets or blocks 22. The drain tube connection 27 can of course be molded in place during formation of the drip tray 29.

In addition to the good heat insulation provided .by the foamed resin components of the heat exchanger which prevents. the collection of condensate on or adjacent the end turns, the heat exchangersof the present invention possess a number of additional advantages. As the foarned end blocks completely enclose and anchor each end turn, the vibration wear and noise sometimes encountered with heat exchangers having metal clamps or end sheets are eliminated.

While there has been shown and described particular embodiments of the present invention it will be understood that the invention is not limited thereto and it is intended by the appended claims to cover all such modilil cations as come Within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An evaporator structurecomprising a serpentine conduit including a plurality of spaced passes series connected by end turns at the opposite ends of said structure and bodies of rigid foarned plastic encapsulating and supporting the end turns at each end of said structure, said bodies of foam plastic forming the sole means for supporting and holding said passes in spaced relation.

. 2. A unitary evaporator and drip tray structure comprising an evaporator component and a drip tray component below said evaporator component for collecting condensate owing from said evaporator component, said structure comprising a unitary body of foamed plastic insulating material forming the end sheets at opposite ends of the evaporator structure and said drip tray component, said evaporator structure including a serpentine conduit including a plurality of spaced horizontal passes series connected by end turns, said end turns being encapsulated in and held in spaced relation solely by the foamed lastic insulating material forming said end sheets.

3. A unitary evaporator and drip tray structure comprising an evaporator component and a drip tray component below said evaporator ,component lfor collecting condensate flowing from said evaporator component, said structure comprising a unitary body of foamed plastic insulating material forming the opposite ends of the evaporator structure and said drip tray component, said evaporator structure including a plurality of spaced horizontal passes series connected by end turns, said end turns being encapsulated in and held in spaced relation solely by said foamed plastic insulating material.

4. A unitary evaporator and drip tray structure cornprising an evaporator component including a conduit comprising end turns at opposite ends of said evaporator component, and a unitary body of rigid foamed `plastic material including spacedl end portions respectively encapsulating and supporting said end turns at opposite ends of said evaporator component and a connecting portion of foamed plastic material connecting said spaced end portions and forming a drip tray below said evaporator component, said foam plastic material providing the sole means for supporting said end portions in spaced relation.

References Cited by the Examiner UNITED` STATES PATENTS 2,047,249 7/36 Ballard 62-225 2,148,238 2/39 Krackowizer 62-291 3,006,979 10/61 Rich 165-135 RCBERT A. OLEARY, Primary Examiner.

WILLIAM I. WYE, Examiner. 

1. AN EVAPORATOR STRUCTURE COMPRISING A SERPENTINE CONDUIT INCLUDING A PLURALITY OF SPACED PASSES SERIES CONNECTED BY END TURNS OF THE OPPOSITE ENDS OF SAID STRUCTURE AND BODIES OF RIGID FOAMED PLASTIC ENCAPSULATING AND SUPPORTING THE END TURNS AT EACH END OF SAID STRUCTURE, SAID BODIES OF FOAM PLSTIC FORMING THE SOLE MEANS FOR SUPPORTING AND HOLDING SAID PASSES IN SPACED RELATION. 